SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d68daddf164ff139bc5976fa2f13d5702d4daf3cf315ffba1ca757bdbaf5527' 
  AND token = 'au8JSS8sueqW/zvzftM7nTfOM6uvFQ+uglN375IkaKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}